Vintage A/C - intermittent noise from control panel

[Chicken Legs]

I just purchased a 62 Fairlane with aftermarket a/c in working condition. The issue is that sometimes there is a loud noise (much like a squealing belt) coming from the control panel. It only does it intermittently when the a/c control button is pushed. Running the fan by itself does not produce the noise. I'm having a hard time figuring it out. Other than the fan motor what could be making the noise?

[rspears]

I just purchased a 62 Fairlane with aftermarket a/c in working condition. The issue is that sometimes there is a loud noise (much like a squealing belt) coming from the control panel. It only does it intermittently when the a/c control button is pushed. Running the fan by itself does not produce the noise. I'm having a hard time figuring it out. Other than the fan motor what could be making the noise?

The only moving parts in your AC system are the AC compressor and the blower/fan. The "control panel" is just electrical switches, nothing to make noises. Have you checked the belt driving the AC Compressor? The only thing inside the car that could "squeal" is a blower/fan bearing that's failing, and it would be the same in heat mode as AC, so I'd bet a cookie that the noise is the belt loose under the hood, and just sounding like it's coming from the dash.

[glennsexton]

I'm thiunking belt? Is the belt good and tight i.e., no more that 1/2" deflection?

[Mike P]

".....It only does it intermittently when the a/c control button is pushed......"

I'm going to guess it's probably a loose belt too. On many of the aftermarket AC systems the compressor cycles on and off to control the temperature. The intermittent squeal is likely when the compressor kicks back on until it comes up to speed.



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[Chicken Legs]

Im with you in that it makes no sense in that there should be no moving parts from the control panel. I'm well aware of what a belt squeal sounds like. I'm thinking maybe its a vent door issue. The tag on the unit is Victory Climate. The door works off the control panel with an actuator. Ima check the location of the door and see if it changes when the noise is present. Thanks for the replies.

[rspears]

Im with you in that it makes no sense in that there should be no moving parts from the control panel. I'm well aware of what a belt squeal sounds like. I'm thinking maybe its a vent door issue. The tag on the unit is Victory Climate. The door works off the control panel with an actuator. Ima check the location of the door and see if it changes when the noise is present. Thanks for the replies.

Victory Climate Systems is a Fort Worth, TX group that's a relatively new player, established in 2010 when they purchased a bunch of component companies. Their website remains "Under Construction" but seems focused on RV & military.

In my experience any movement of vent doors or dampers (Defrost or Recirculation, for example) are one time events, open or closed, not modulating. You engage the system, set the controls which positions any dampers, and then the only thing that "cycles" is the compressor on & off like Mike mentioned. I've never seen a system that "modulates" unless it has a specific temperature set point with a feedback loop from interior temp, and most of those just adjust the "on time" of the compressor. Some high end systems may modulate an outside air damper, but I've not seen it. No offense, but belt squeal can be a wide range of sounds, especially on an AC compressor which may just barely slip. A worn belt may have spots that slip more than others, adding to the weird sounds they can make.

It'll be interesting to hear what you find is "squealing"!!

[Chicken Legs]

Thanks for the detailed reply. With that and your mention of 'engage the system and set the controls which positions any dampers' what if there is a voltage drop or intermittent short that causes a damper to close?

[Chicken Legs]

I have a 10 second clip of it I can send if anyone is curious.

[rspears]

Sent you a PM with my email, if you can't post the clip here.

[rspears]

That's a really big clip - 18MB! That sounds more like a rotating metal to metal rub to me. How fast were you going, and how does the rate of the sound compare to your RPM? If you accelerate while it's "chirping" does the rate of the chirp change in proportion? Does it make the same noise parked with the AC on? Wondering if maybe your AC clutch has something loose or bent, or maybe a bad bearing? Clutch freewheeling is fine, but then when it locks for the compressor there's a rub/bearing noise?

[40FordDeluxe]

My vintage air controller on my Camaro doesn't squeal, but occasionally with the lever in the off position, the controller turns on the AC system on it's own. Of course it is out of warranty and they are out of stock. The AC does work if you turn it on. But it coming on by it's self in the off position is odd and a pain.

[Chicken Legs]

I rechecked the pressure on the low and high side, and they are in check. I'm still a little low on the low side but it blows 47degree currently. Some conversation brought up that it may be an expansion valve sticking, which causes it to vibrate, hence the noise. I drove a little over the weekend and it didnt make the noise, so,,,,,,,,,,,,,,